1. Field of the Invention
The present invention relates to an improved apparatus for drying foodstuffs.
More specifically, the invention relates to an apparatus of the above kind, particularly studied and realised for removing humidity from leaf products, permitting optimised power consumption for every situation.
2. Brief Description of the Art
As it is well known, many apparatuses or machines exist for drying leaf products, such as vegetables or fruit, or for removing water from the same. Particularly, different kind of said apparatuses or machines exist exploiting centrifugal force for removing said residual humidity.
Above mentioned machines are usually comprised of a rotating basket, with vertical or horizontal axis, containing the product to be dried. Said basket is driven by an electric, hydraulic or pneumatic motor. Drying cycle is a batch cycle, providing a basket loading step, a centrifugation step and a product discharge step.
Rotation speed and working time can be usually adjusted. Some of these machines are loaded and unloaded on the same side and thus mechanisms for upturning the same are provided. Other machines are loaded and unloaded from opposite ends.
Known machines providing electric motors usually use asynchronous three-phase motors. Said motors overheat at low speed due to their design criteria, i.e. during the loading and unloading steps, and, moreover, they have a peak of power absorption at the start, thus when beginning the centrifugation, with a very low torque generated.
In view of the above, known electric centrifugal apparatuses must provide oversized motors, with cooling device for operation at low speed. This increases their dimensions, thus making the same not convenient.
Furthermore, asynchronous three-phase motors must provided transmission pulleys for reduction of number of revolution, as well as electronic speed regulators (inverter), the adjustment range of which is in any case very limited (ratio between about 1 and about 3).
As far as centrifugal machines or apparatuses driven by hydraulic motors, it is known that they can have an even torque with low regime, but that they are huge, being activated by suitable stations. Therefore, they are more Complex to be realised and assembled but, particularly, in case of oil leakages, they can contaminate the product.